* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Reproduction and Development
Survey
Document related concepts
No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Neocentromere wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Genetic engineering wikipedia , lookup
Oncogenomics wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
X-inactivation wikipedia , lookup
Mir-92 microRNA precursor family wikipedia , lookup
Designer baby wikipedia , lookup
Genome (book) wikipedia , lookup
History of genetic engineering wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Point mutation wikipedia , lookup
Transcript
Reproduction and Inheritance Overview Species = group of closely related organisms that share certain characteristics and can produce new individuals through reproduction For any species to survive, they must reproduce All individuals will die but their species will live on through reproduction Offspring begins a period of development that ends in adulthood Once an individual reaches adulthood, it is usually able to reproduce and continue the species Types of Reproduction There are two methods of reproduction: ◦ Asexual ◦ Sexual Asexual reproduction involves just one parent ◦ Results in one or more offspring that are genetically identical to the parent Types of Reproduction Sexual reproduction involves two parents ◦ Some genetic material (DNA) comes from each parent ◦ The result is an organism that may be similar to one or both parents but is not identical to either Asexual Reproduction Organisms that reproduce asexually produce offspring in a variety of ways. ◦ Some just divide in two: produces two new individuals The parent becomes an offspring Eg: Ameba divides into two ameba ◦ Some organisms produce special cells that have a complete set of genetic information These parts develop into new cells Eg: Mold spores reproduce mold Asexual Reproduction ◦ Others produce an outgrowth of the body that detaches to become a separate individual ◦ Some plants can regrow from broken pieces of the larger plant Eg: Hydra bud off a smaller version of itself Eg: Strawberry plants can have runners that produce another strawberry plant In all cases the DNA is exactly the same in both Examples of Asexual Reproduction Sexual Reproduction Offspring get half of their genes from one parent and the other half from another ◦ The genes are carried on chromosomes in sex cells Sex cells = gametes (egg or sperm cells) = haploid cells Haploid = ½ of the number of chromosomes Sexual Reproduction ◦ Two gametes join in fertilization Each parent supplies one of the gametes with half of their genetic information Sperm from father = formed through spermatogenesis Egg from mother = formed through oogenesis Sexual Reproduction Offspring combine genes inherited from each gamete An offspring gets only half of its DNA from each parent so it will not be identical to either Each offspring gets a unique combination of genes from the parents, each offspring is different from its siblings (brother or sisters) Cloning Cloning = technique that accomplishes the same end result as asexual reproduction ◦ Way of making identical genetic copies Example: if you cut a piece of stem from a plant and it grows roots and develops into a new plant, it would be genetically identical = clone Cloning It has recently been possible to clone animals that normally reproduce by sexual reproduction ◦ The nucleus of an egg is removed and replaced with a nucleus that contains 100% of the genes from a single parent. ◦ The egg is allowed to develop normally ◦ The new organism that results is a clone of the parent cell ◦ In mammals, the egg would be implanted into the body of a female to develop Cloning has been possible with complex organisms like sheep or pigs Cloning Cell Division Cell division = orderly separation of one cell into two Before the cell can divide the DNA is duplicated (copied) The process that produces two complete sets of the DNA = mitosis ◦ Mitosis produces 2 cells that have a full set of identical genes and chromosomes Unless a mutation occurs Cell Division Due to mitosis, each new cell has all the information it needs to function properly One-celled organisms make use of mitosis for asexual reproduction Multi-cellular organisms mainly use mitosis for growth and for cell replacement and repair Cell Division There is another type of division, meiosis Meiosis = process that divides the genetic material in a way that results in the production of the sex cells required by organisms that reproduce sexually Each sex cell has half the genetic information, this is done through meiosis Mitotic Division/Mitosis During mitotic cell division (mitosis), the double stranded chromosomes that are visible during mitosis split into two identical single strands and move to opposite ends of the cell Mitotic Division/Mitosis The process is done when the cytoplasm divides ◦ Results in two small but genetically identical cells Interphase Interphase is a period of growth and genetic replication Prophase Prophase is a stage where two centrioles form and move toward poles The nucleus disappears Chromatin coils into chromosomes Metaphase In metaphase, chromosomes line up at the equator Anaphase Anaphase – fibers pull the chromatids toward the centrioles at the poles Chromosomes are pulled into chromatids Telophase During Telophase, Chromatids are at the opposite poles Chromatids unwind into chromatin ◦ A threadlike structure of DNA Cytokinesis During cytokinesis, the two cells split apart into 2 daughter cells Meiotic Division/Meiosis Gametes (sperm + eggs) formed during meiotic division have only half of the parents genetic material ◦ Only one chromosome of each parents pair is present in the cell (rather than both chromosomes) A cell needs two sets to function When the sperm and egg combine during fertilization, the chromosomes pair up and all the needed genetic information is present Meiotic Division/Meiosis Meiotic division starts with a body cell with full number of chromosomes ◦ Depending on the species the organisms contains one or more pairs of chromosomes to determine traits The process occurs in two phases. It ends with 4 cells that contain ½ of the genetic material found in normal body cells. This type of cell division can lead to sexual reproduction. Meiotic Division/Meiosis During the first phase of meiosis, the double stranded chromosomes line up in pairs in the center of the cell Then are separated moving to opposite ends of the cell The cell then physically divides into two cells The second phase of meiosis involves the division of each of the new cells Meiotic Division/Meiosis In each of the cells ◦ The chromosomes line up single file in the center Each chromosome still has two strands ◦ The strands are separated and move to opposite ends of the cell ◦ The cells then split into two Now there are 4 cells, each has half a set of chromosomes ◦ Only one of the original pair in each cell ◦ Can be called either sperm or egg, haploid, gametes, or sex cells Phase 1 Interphase – Growth and genetic replication Prophase I – each chromosome duplicates and remains closely associated ◦ Called sister chromatids Metaphase I – homologous chromosomes align at the equator ◦ Crossing over can occur at this stage Anaphase I – homologous pairs separate with the sister chromatids remaining together Telophase I – two daughter cells are formed with one chromosome from the homologous pair Phase 2 – gamete formation Prophase II – DNA has not replicated – no interphase Metaphase II – chromosomes align at the equator Anaphase II – centromeres divide and sister chromatids migrate separately to each pole Telophase II – cell division is complete ◦ 4 haploid daughter cells are formed Meiotic Division/Meiosis Meiosis and mitosis have very different end results ◦ Mitosis = 2 exactly similar cells ◦ Meiosis = 4 cells with half the number of chromosomes Meiosis in males and females is exactly the same ◦ ◦ ◦ ◦ Except for the division of cytoplasm Males have four functional sperm An egg divides unequally There is one large cell that becomes the egg and three smaller nonfunctional cells Meiosis as a Source of Variation Meiosis provides a source of variation because it allows ½ of the genetic material to come from each parent Meiosis is responsible for most of the genetic variation among sex cells in an individual Two members of each chromosome carry different ways of expressing traits When random sex cells pair up it can lead to many possible combinations in traits Meiosis as a Source of Variation Variation can also occur by exchange of parts of chromosomes ◦ Chromosomes pair up and parts of the chromosome switch ◦ It is called crossing over After the chromosomes split apart each chromosome is now even more unique Meiosis as a Source of Variation In all, no two sex cells are the same. Each cell is unique Summary of Mitotic and Meiotic Cell Division Points of Comparison Mitotic Division Meiotic Division Number of cell divisions One Two Exchange of genetic material between chromosomes No Yes Number of functioning cells Two produced from original Four sperm (in males) or one egg (in females) Genetic makeup of final cells produced Same as original Highly variable gametes produced, each containing half of the genetic information of the original Function of cells produced in multicellular organisms Growth or replacement of body cells Or Asexual Reproduction Combine to form the zygote for reproduction Genetic Disorder Paper This is a research paper ◦ Your job is to explain your chosen genetic disorder in detail. Someone reading your paper could walk away and teach someone else about this disorder. Introduction ◦ ½ to 1 page - Brief/General overview of the disorder Body of the paper ◦ 3-4 pages cite research and ideas (name, year) ◦ ½ to 1 page conclusion – summarize your greatest argument Literature Cited ◦ Name, title, year, journal, pages ◦ Web – name, title, website, year ◦ AT LEAST 5 different sources – Creditable sources! Wikipedia is not a creditable source Size 12 font, arial, 1” margins, Double spaced Due date:______________ Inheritance Inheritance = act of genetic transmission of traits from parents to offspring During meiosis sex cells are created. ◦ These cells have a haploid number of chromosomes There also may be crossing over or mutations to add to the variation in inheritance It is also random which egg and sperm will combine to form the zygote (cell resulting from fertilization) Inheritance in Plants Plants – 2 types of pollination ◦ Cross-pollination is the fertilization of the egg from one plant by the sperm of another plant Animals and wind aid in this process. ◦ Self-pollination is the fertilization of an egg by the sperm of the same plant. May be from the same flower or another flower on the same plant Inheritance Gene = a segment of DNA (on a chromosome) that contains the code for a specific trait Allele = one of two or more alternative forms of a gene that are found at the same place on the chromosome Inheritance The dominant allele will always show itself as a physical, behavioral, or functional trait The recessive allele will only show itself in the absence of a dominant allele Gene Expression A gene is expressed when the gene produces a protein Sometimes a gene will not function the same when under different environmental conditions ◦ Plant being white in the absence of sunlight ◦ Sunlight is needed to stimulate the gene responsible for producing chlorophyll Gene Expression Gene expression is the result of activated genes You would be a real mess if every gene was expressed in every cell Gene Expression Genotype – the pair of alleles Phenotype – the physical, behavioral, or functional trait that results from the genotype Gene Expression Homozygous ◦ Recessive – 2 like alleles that are recessive in nature ◦ Dominant – 2 like alleles that are dominant in nature Heterozygous – one dominant and one recessive allele Punnett Square Punnett squares are used to simulate a cross between parental characteristic and predict the probability of the traits being passed onto the offspring Shared Gene Expression Shared dominance is when both alleles show up as the phenotype ◦ A pink rose has both a red and white allele = pink Codominance is when both show up separately as traits – a roan horse has red and white hairs Shared Gene Expression Some traits are linked to the sex chromosomes ◦ Balding Inheritance How can two green plants produce a yellow plant? Mutations What is a mutation? ◦ Any change in the normal DNA sequence Only mutations that occur in the sex cells (egg and sperm ) can be passed onto the next generation ◦ Called germ cell mutations Mutations Mutations that occur in the body and that are passed onto the daughter cells during mitosis are somatic cell mutations Two classifications of mutations are chromosome and gene Chromosome Mutations Chromosomes mutations occur during cell division when the DNA is being shuffled and result in structural change to the DNA or deletion of an entire chromosome. 4 major types of mutations occur during cell division ◦ Translocation, Deletion, Inversion, Nondisjunction Chromosome Mutations ◦ Translocation – when a piece of DNA breaks away from one chromosomes and attaches to a different chromosome ◦ Deletion – when a piece of , or an entire chromosome is lost or is not replicated Chromosome Mutations ◦ Inversion – when a piece of DNA breaks away and then reattaches in the opposite direction ◦ Non-disjunction or non-separation – when a chromosome fails to split apart during cell division, resulting in an extra chromosome in one cell and one less in the other daughter cell Genetic Mutations Gene mutations ◦ Smaller scale than a chromosome mutation ◦ It may involve a single nitrogen base or a larger piece of DNA Point mutation ◦ When a single nitrogen base is added, substituted, or removed Any of these three changes of a gene result in a different protein structure Why? ◦ Addition or deletion causes the code to be shifted up or down – similar to hitting the space bar or backspace on the computer ◦ Called a frame-shift mutation Cause of Mutations Mutagens- any environmental factor that can damage DNA Increased amounts of energy or chemicals that interfere with the process of DNA replication can cause mutations ◦ ◦ ◦ ◦ ◦ Radiation Sunlight – ultra-violet radiation Atomic bombs – gamma radiation asbestos, radon gas – alpha and beta radiation All energy Causes of Mutations Other agents ◦ Cigarette smoke ◦ Certain viruses ◦ Chemicals in food Carcinogen – anything that causes or is linked to the cause of cancer Cancer is related to: ◦ Inherited genes – some people are more likely to get cancer because of their genetic make-up ◦ Frequency of exposure and the intensity of the exposure to cancer causing agents (up the odds) ◦ Infection by virus that inhibit the normal process of DNA replication or cell division Causes of Mutations All of these affect the process of cell division, either genetically or functionally ◦ Oncogene – gene that when affected can cause a cell to become cancerous Cancer is a cell or group of cells that are out of control in terms of cell division ◦ Cancer cells do not have natural stops for cell division Types of Cancer Results in tumors – abnormal masses ◦ Benign – do not spread ◦ Malignant – break away from the original mass and spread Types of Cancer Three classifications of cancer ◦ Lymphoma – solid tumors in blood cell producing tissues Types of Cancer Leukemia – affect white blood cells Types of Cancer Carcinoma – skin and nervous tissue Blood Type Blood Type Positive and negative blood types work in the same fashion Positive has a protein names after the rhesus monkey and cannot donate to people with a negative blood type Blood Types History of blood use and beliefs Universal donor = Can give blood to anyone Universal recipients = Can receive blood from anyone